Non-contact power charging system and control method thereof

ABSTRACT

A non-contact power charging, in which power transmission can be interrupted when foreign materials are deposited on a charge plate of the non-contact power charging system. A charging operation can be continuously maintained at a stable voltage even if a non-contact power receiving apparatus moves by touching or displacement on the charge plate of the non-contact power charging system in the charging operation. Charging efficiency is improved.

CLAIM OF PRIORITY

This application claims the benefit of Korean Patent Application No.10-2008-0015114 filed on Feb. 20, 2008, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a power charging system, and moreparticularly, to a non-contact power charging system and a controlmethod thereof, in which power transmission can be interrupted whenforeign materials are deposited on a charge plate of the non-contactpower charging system, a charging operation can be continuouslymaintained at a stable voltage even if a non-contact power receivingapparatus moves by touching or displacement on the charge plate of thenon-contact power charging system in the charging operation, and thuscharging efficiency can be improved.

2. Description of the Related Art

Portable electronic devices, such as cellular phones, personal digitalassistants (PDAs), portable media players (PMPs), digital multimediabroadcasting terminal (DMB terminals), MPEG audio layer 3 (MP3) playersor notebook computers, cannot be plugged into a regular power source athome or office since they are generally used while the users are moving.Accordingly, the portable electronic devices are equipped with batteriesor rechargeable batteries.

A charging system has been used to charge electric power, supplied fromthe regular power source, to the batteries or a battery pack of theportable devices via power supply lines or power supply connectors.However, when the charger and the batteries are connected ordisconnected to replenish the electric power of the batteries with thisconnector supply system, an instant discharge may happen because of thepotential differences between the charger connector and the batteryconnector. Hence the foreign substances will be gradually gathered onboth connectors and finally there may be a fire disaster. Further, thecollected humidity thereon will cause the discharge of the battery andother problems will be involved like the declining battery life, the lowbattery quality, and so on.

To solve the above-mentioned problems of the connector supply system,non-contacting charging systems have been developed. In thisnon-contacting charging system in accordance with the prior art, thedevice having the battery to be charged is placed over the primary coilof the non-contacting charging system and the battery will be charged bya secondary coil of the battery. The battery is charged with the inducedelectricity from the induced electromotive force of the secondary coilby the generated magnetic field from the primary coil.

The existing non-contacting charging systems with the prior art can onlybe used to supply the electricity to the portable devices. There arelimited practical uses because they cannot be used in variousalternatives.

Besides, if a metal is placed inside the effective radius of thegenerated magnetic field of the primary coil, there would be a lot lossof the electricity in the primary coil due to the changes of themagnetic field, so that non-contacting charging system may be damaged.

SUMMARY OF THE INVENTION

The present invention has been made to solve the foregoing problems withthe prior art, and therefore the present invention is directed toprevent a non-contact power receiving apparatus and a non-contact powertransmission apparatus by stopping power transmission when a foreignmaterial is deposited on a charge plate.

The present invention is also directed to improve charging efficiency byensuring that a charging operation be performed at a stable voltage evenif the non-contact power receiving apparatus moves by touching ordisplacement on the charge plate of the non-contact power transmissionapparatus while being powered.

Further, the present invention is also directed to protect a batterycell from a magnetic field created by primary and secondary charge coressuch that the battery cell can be stably charged.

According to an aspect of the present invention, there is provided anon-contact power charging system, including a non-contact powertransmission apparatus generating a power signal at a primary chargecore thereof; and a non-contact power receiving apparatus receiving thepower signal from the non-contact power transmission apparatus so as tobe charged with power by the control of the non-contact power chargingsystem. The non-contact power receiving apparatus includes a secondarycharge core generating induced current in response to the primary chargecore of the non-contact power transmission apparatus; a rectifier blockconnected to the secondary charge core to rectify the induced current; acharge IC block causing to charge a battery cell with the power from therectifier block; a received power monitor module monitoring the powerreceived through the secondary charge core; and a power receiver controlunit constructed to control the rectifier block, the charge integratedcircuit (IC) block and the received power monitor module, and to controlidentifier (ID) generation and a charge status signal. The receivedpower monitor module includes a low voltage monitor module comparing anddiscerning whether or not the received power is detected to have a lowvoltage and a high voltage monitor module comparing and discerningwhether or not the received power is detected to have a high voltage.

According to another aspect of the present invention, there is provideda control method of a non-contact power charging system, which includesa non-contact power transmission apparatus generating a power signal ata primary charge core thereof and a non-contact power receivingapparatus receiving the power signal from the non-contact powertransmission apparatus so as to be charged with power. The controlmethod includes procedures:

transmitting, at the primary core of the non-contact power transmissionapparatus, an object detection signal including a call signal that calla unique ID value from the non-contact power receiving apparatus, andstanding by for a response signal;

discerning whether or not a normal unique ID signal is received from thenon-contact power receiving apparatus by discerning a signal detectedaccording to load modulation by the primary charge core;

if it is discerned that a normal unique ID signal is received from thenon-contact power receiving apparatus, generating, at the primary chargecore through a gate driver module of the non-contact power transmissionapparatus, a full power transmission signal;

requesting charge status information from the non-contact powerreceiving apparatus and adjusting charge level based on the chargestatus information received from the non-contact power receivingapparatus; and

if fully-charged state information is received from the non-contactpower receiving apparatus, terminating a charging operation anddisplaying fully-charged state on a liquid crystal display panel or acharge status indicator light emitting module.

Here, the procedure of discerning whether or not a normal unique IDsignal is received from the non-contact power receiving apparatus bydiscerning a signal detected according to load modulation by the primarycharge core, includes: if the signal detected according to loadmodulation by the primary charge core is not a normal signal that hasnormal ID data transmitted from the non-contact power receivingapparatus, converting into a foreign material detection mode; and if adetected foreign material is metal or an electronic device, displaying aforeign material error on the liquid crystal display panel or the chargestatus indicator light emitting module and terminating a chargingoperation of a corresponding charging block.

Further, the procedure of adjusting charge level based on the chargestatus information received from the non-contact power receivingapparatus, includes: requesting data information on charge statusinformation from the non-contact power receiving apparatus; receivingthe charge status information transmitted from the non-contact powerreceiving apparatus, the charge status information including chargedamount information and voltage data of received power; analyzing anddiscerning data on the charge status information on the power signal,received from the non-contact power receiving apparatus; and calculatinga frequency of the power signal in order to compensate for transmissionpower based on the voltage data, received from the non-contact powerreceiving apparatus, and transmitting a power signal at a compensatedfrequency.

According to a further aspect of the present invention, there isprovided a control method of a non-contact power charging system, whichincludes a non-contact power transmission apparatus generating a powersignal from a primary charge core thereof, and a non-contact powerreceiving apparatus receiving the power signal from the non-contactpower transmission apparatus so as to be charged with power. The controlmethod includes procedures of:

detecting, at the non-contact power receiving apparatus in a standbymode for receiving the power signal, detecting a call signal transmittedtogether with an object detection signal from the primary charge core ofthe non-contact power transmission apparatus to call a unique ID valuefrom the non-contact power receiving apparatus, and transmitting asignal related with the call ID value of the non-contact power receivingapparatus to the non-contact power transmission apparatus;

converting into a charge standby mode after the unique ID value istransmitted, rectifying the power signal transmitted from thenon-contact power transmission apparatus and charging a battery cellwith the rectified power signal;

discerning whether or not the power signal transmitted from thenon-contact power transmission apparatus has a reference voltage, andtransmitting a voltage adjustment signal to request voltage step-up ifthe discerned power signal is below the reference voltage or to requestvoltage step-down if the discerned power signal is above the referencevoltage;

after the voltage adjustment signal is transmitted, if a receivedvoltage is the reference voltage, generating a signal indicative ofnormal reception; and

discerning whether or not the battery cell is in fully charged status,and if the battery cell is in fully charged status, terminating acharging operation.

As set forth above, the present invention can prevent the non-contactpower receiving apparatus and the non-contact power transmissionapparatus from being damaged by stopping power transmission when aforeign material is deposited on the charge plate.

Further, the present invention can also improve charging efficiency byensuring that a charging operation be performed at a stable voltage evenif the non-contact power receiving apparatus moves by touching ordisplacement on the charge plate of the non-contact power transmissionapparatus while being powered.

Moreover, the present invention can also protect the battery cell from amagnetic field created by the primary and secondary charge cores suchthat the battery cell can be stably charged.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a schematic configuration view illustrating a non-contactpower transmission apparatus of a non-contact power charging system inaccordance with the present invention;

FIG. 2 is a schematic configuration view illustrating a non-contactpower receiving apparatus of the non-contact power charging system inaccordance with the present invention;

FIG. 3 is a flowchart illustrating a non-contact power transmissionprocess of the non-contact power charging system in accordance with thepresent invention;

FIG. 4 is a flowchart illustrating a non-contact power receiving processof the non-contact power charging system in accordance with the presentinvention;

FIG. 5 is a control flow diagram illustrating a non-contact powertransmission process of the non-contact power charging system inaccordance with the present invention;

FIG. 5 is a control flow diagram illustrating a non-contact powerreceiving process of the non-contact power charging system in accordancewith the present invention;

FIGS. 7 and 8 are circuit diagrams illustrating the non-contact powerreceiving apparatus of the non-contact power charging system inaccordance with the present invention;

FIG. 9 is an exploded perspective view illustrating the construction ofthe non-contact power receiving apparatus of the non-contact powercharging system in accordance with the present invention;

FIG. 10 is a side cross-sectional view of FIG. 9;

FIGS. 11 and 12 are graphs illustrating power control efficiencies ofthe prior art;

FIGS. 13 and 16 are graphs illustrating power control efficiencies ofthe non-contact power charging system in accordance with the presentinvention;

FIG. 17 is a graph illustrating efficiencies of repeatedcharge/discharge test on the non-contact power receiving apparatus ofthe non-contact power charging system in accordance with the presentinvention; and

FIGS. 18 and 19 illustrate operations of the non-contact power chargingsystem in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, the present invention will be described more fully withreference to the accompanying drawings, in which exemplary embodimentsthereof are shown.

FIG. 1 is a schematic configuration view illustrating a non-contactpower transmission apparatus of a non-contact power charging system inaccordance with the present invention; FIG. 2 is a schematicconfiguration view illustrating a non-contact power receiving apparatusof the non-contact power charging system in accordance with the presentinvention; FIG. 3 is a flowchart illustrating a non-contact powertransmission process of the non-contact power charging system inaccordance with the present invention; FIG. 4 is a flowchartillustrating a non-contact power receiving process of the non-contactpower charging system in accordance with the present invention; FIG. 5is a control flow diagram illustrating a non-contact power transmissionprocess of the non-contact power charging system in accordance with thepresent invention; FIG. 5 is a control flow diagram illustrating anon-contact power receiving process of the non-contact power chargingsystem in accordance with the present invention; FIGS. 7 and 8 arecircuit diagrams illustrating the non-contact power receiving apparatusof the non-contact power charging system in accordance with the presentinvention; FIG. 9 is an exploded perspective view illustrating theconstruction of the non-contact power receiving apparatus of thenon-contact power charging system in accordance with the presentinvention; FIG. 10 is a side cross-sectional view of FIG. 9; FIGS. 11 to16 are graphs illustrating power control efficiencies of the non-contactpower charging system in accordance with the present invention; FIG. 17is a graph illustrating efficiencies of repeated charge/discharge teston the non-contact power receiving apparatus of the non-contact powercharging system in accordance with the present invention; and FIGS. 18and 19 illustrate operations of the non-contact power charging system inaccordance with the present invention.

Referring to FIGS. 1 to 19, a non-contact charging system A of thepresent invention includes a non-contact power transmission apparatus 10that is constructed to transmit a power signal to a non-contact powerreceiving apparatus 30 without actual contacts.

As shown in FIG. 1, the non-contact power transmission apparatus 10includes a central control unit and a full bridge resonant converter 22,which act to transmit a power signal to the non-contact power receivingapparatus 30 without actual contacts.

The non-contact power transmission apparatus 10 also includes a gatedriver module 23, which causes the full bridge resonant converter 22 totransmit a converted power signal, and a received signal processingmodule 24, which processes a signal transmitted from the non-contactpower receiving apparatus and sends the processed signal to the centralcontrol unit 21.

The non-contact power transmission apparatus 10 also includes a powertransmission apparatus case (not shown). The power transmissionapparatus case includes, on the front side thereof, a power on/offswitch, an input panel for signal input, a liquid crystal display (LCD)panel 153 and a charge status indicator light emitting diode (LED)module 154. The LCD panel 153 and the LED module 154 serve to displaythe status and the charge status of a non-contact charge plate (notshown) and the non-contact power receiving apparatus 30. Inside thepower transmission apparatus case, a power supply unit 25 is installed.

As such, as shown in FIG. 1, the non-contact power receiving apparatus30 implemented as a battery of a mobile device, such as a mobile phone,a personal digital assistant (PDA), a portable multimedia player (PMP),a digital multimedia broadcasting terminal (DMB terminal), a movingpicture experts group (MPEG) audio layer 3 player (MP3 player) or anotebook computer, is mounted on the charge plate of the non-contactpower transmission apparatus. When the non-contact power receivingapparatus is placed on the charge plate, the non-contact powertransmission apparatus 10 starts a charging operation by detecting theplacement of the non-contact power receiving apparatus 30.

Below a description will be given of the construction of the centralcontrol unit 21 controlling the charging operation of the non-contactpower transmission apparatus 10. As shown in FIG. 1, the central controlunit 21 includes a power supply block 211 connected to the power supplyunit 25 to supply power to the non-contact power transmission apparatus10; a signal output block 212 outputting an indicator signal to the LCDpanel 153 and the charge status LED module 154; a gate output signalprocessing block 213 connected to the gate driver module 23 to transmita control signal in response to an output power signal from a primarycharge core 13; a received signal processing block 214 connected to theprimary charge core 13 to process a signal transmitted from the receivedsignal processing module 24, which processes a signal transmitted fromthe non-contact power receiving apparatus 30; and a main controller 210controlling parts of the non-contact power transmission apparatus 10including the power supply block 211, the signal output block 212, thegate output signal processing block 213, the received signal processingblock 214 and so on.

The power supplied to the power supply unit 25 may be provided from auniversal serial bus (USB) port of a computer, an alternating current(AC) adaptor, a cigar jack and so on.

The central control unit 21 also includes a temperature detector 26,which detects the temperature of the non-contact power transmissionapparatus 10 during the charging operation. The central control unit 21can be constructed to interrupt the charging operation when atemperature detected by the temperature detector 26 indicatesoverheating, or to suspend the operation of the whole system when thedetected temperature indicates overheating of the whole part of thenon-contact power transmission apparatus 10.

A current sensing member may also be provided in each of the powersupply unit 25, the gate driver module 23, the full bridge resonantconverter 22 and the received signal processing module 24 in order todetect a flow of electric current. The non-contact power transmissionapparatus 10, particularly, the central control unit 21 can beconstructed to interrupt the charging operation or the operation of thesystem, and generates a corresponding signal when the current sensingmember detects an over-current or over-voltage state from acorresponding part.

The non-contact power receiving apparatus 30 is an apparatus thatreceives a power signal from the non-contact power transmissionapparatus 10. As shown in FIG. 2, the non-contact power receivingapparatus 30 generally includes a secondary charge core 32 having aconstruction corresponding to that of the primary charge core 13 of thenon-contact power transmission apparatus 10 so as to generate inducedcurrent; a rectifier block 33 connected to the secondary charge core 32to rectify induced current; a smoothing filter block 34 connected to therectifier block to filter current and power; a charger integratedcircuit (IC) block 36 connected to the rectifier block 33 to charge abattery cell 35 with power; a protection circuit module (PCM) block 37disposed between the charger IC block 36 and the battery cell 35 todetect current charged to the battery cell 35 and transmit the chargestatus information of the battery 35 to a power receiver control unit 39so as to detect the status of the battery, such over-voltage,under-voltage, over-current and short-circuit; and a static voltageregulator block 38 supplying power to the PCM block 37. The powerreceiver control unit is also provided in the non-contact powerreceiving apparatus 30, and is constructed to control the rectifierblock 33, the smoothing filter block 34, the charger IC block 36, thePCM block 37 and the static voltage regulator block 38 and to monitor anoccurrence of an identifier (ID) and a charge status.

The non-contact power receiving apparatus 30 also includes a receivedpower monitor module 31, which monitors power received through thesecondary charge coil 32, in order to detect whether or not power isstably received. A reference voltage of a power source, which isreceived as above, can be variously selected according to the detailedspecification of the non-contact power charging system A and thenon-contact power receiving apparatus 30. For example, the referencevoltage can be set, generally, in the range from 2 to 20V, and whenapplied to a typical mobile phone device, on the order of 4V.

The received power monitor block 31 includes, as subsidiary componentsthereof, a low voltage monitor module 311 discerning whether or notreceived power has a low voltage and a high voltage monitor module 312discerning whether or not received power has a high voltage.

In the low voltage monitor module 311 as above, the voltage level actingas a reference of a low voltage can be selectively set according to thedetailed specification of the non-contact power charging system A andthe non-contact power receiving apparatus 30. The voltage level may beset −1V or −0.5V when the reference voltage is set 5V as in theforegoing illustration.

Likewise, the voltage level acting as a reference of a low voltage inthe high voltage monitor module 312 can also be selectively setaccording to the detailed specification of the non-contact powercharging system A and the non-contact power receiving apparatus 30. Thevoltage level may be set +1V or +0.5V when the reference voltage is set5V as in the foregoing illustration.

The power receiver control unit 39 includes a power signal processingblock 393 connected to the smoothing filter block 34 to process atransmission signal about data information on a power signal transmittedfrom the non-contact power transmission apparatus 10; a charge signalprocessing block 394 connected to the charge IC block 36 and the PCMblock 37 to process a transmission signal about data information on thecharge capacity and charge status of the battery cell 35; a signalprocessing block 392 processing charge capacity information and datainformation on a unique ID, which are transmitted to the non-contactpower transmission apparatus 10 by the control of a device controller390; and a device memory 391. The device memory 391 stores datainformation on a unique ID, temporarily stores charge capacityinformation and charge status data, which are transmitted from the PCMblock 37 and the charge IC block 36, and storing data transmitted fromthe non-contact power transmission apparatus 10. The device controller390 is also included in the power receiver control unit 39.

Referring to an exemplary construction shown in FIG. 7, a part formonitoring the voltage of power transmitted from the non-contact powertransmission apparatus 10 is implemented as the received power monitormodule 31 separate from the power receiver control unit 39.

As such, the monitoring part can be constructed as a separate modulefrom the power receiver control unit 39. Further, as shown in FIG. 8, asingle control module can be constructed by integrating the powerreceiver control unit 39 with a received power monitor block 31′. In thecase where the power receiver control unit 39 including the receivedpower monitor module 31 (a low voltage monitor block 311′ and highvoltage monitor block 312′) is constructed as a single module, theadvantage is that the construction of the non-contact power receivingapparatus 30 can be simplified, thereby reducing the entire sizethereof. Another advantage is that lines for monitoring received powercan be simplified so as to simplify the entire circuit construction.

While the foregoing embodiment has been illustrated with respect to avoltage-monitoring construction which monitors a received power signalwith reference to the upper or lower limit of a voltage, acurrent-monitoring construction can also be provided alone or incombination with the voltage-monitoring construction. Of course, it canbe constructed to monitor both the voltage and the current in order toensure circuit stability. According to installation conditions, only oneof a voltage-monitoring circuit and a current-monitoring circuit can beprovided. While following embodiments will be illustrated with respectto the upper or lower limit of a voltage, this is not intended to limitthe present invention. Rather, the circuit can also be constructed tomonitor received power using the upper and lower limits of current suchthat power can be stably received.

The non-contact power charging system A as described above has anadvantage in that a power signal transmitted from the non-contact powertransmission apparatus 10 is stably received in the non-contact powerreceiving apparatus 30 such that charging power can be transmitted inoptimized conditions.

Below, a description will be given of the charging operation of thenon-contact power charging system A in accordance with the presentinvention constructed as above.

In the non-contact power transmission apparatus 10 of the non-contactpower charging system A, a power signal is periodically transmitted tothe gate output signal processing block 213, the gate driver module 23,the full bridge resonant converter block 22 and the primary charge core13 through gate signal lines 234 by the control of the central controlunit 21 (standby mode S01). In the standby mode S01, the power signalperiodically transmitted through the primary charge core 13 includes acall signal that request a unique ID from the non-contact powerreceiving apparatus 30, and the process stands by for a response signalto the call signal.

In the procedure of standing by for a response signal after thetransmission of the unique ID call signal in the standby mode S01, anobject is detected using a received detection signal in response to loadmodulation by the primary charge core 13. The object, which can beplaced on the charge plate, may include not only a mobile non-contactpower receiving apparatus 30, such as a mobile phone, a PDA, a PMP, aDMB device, an MP3 player or a notebook computer, but also a metallicobject, a non-metallic object and an electronic device incapable ofnon-contact charging. Accordingly, the non-contact power transmissionapparatus 10 discerns whether or not any one of the above-describedobjects is placed on the charge plate by receiving the detection signalin response to load modulation produced by the object.

In the case of load modulation caused by the presence of thenon-metallic object or the movement of the object, the operation mayconvert to the standby mode S01 unless there is a specific problem.However, in the case of the metallic object or electronic deviceincapable of non-contact charging rather than the non-contact powerreceiving apparatus 30, the charging operation may bring in heating ormalfunction.

To this end, a foreign material is monitored by parasitic metaldetection (PMD). That is, when the detection signal in response to loadmodulation caused by an object is detected by the primary charge core 13and the received signal processing module 24, this procedure is carriedout to discern whether or not the detection signal is a normal signal.Particularly, the procedure discerns whether or not the detection signalis an abnormal signal incapable of signal discerning by comparing thedetection signal with a signal generated by the control of the centralcontrol unit 21. If the object is detected as a foreign material, theprocess converts into a foreign material detection status, causes theLCD panel 153 or the charge status indicator LED module 154 to display aforeign material error (a PMD error) if the foreign material is ametallic object or an electronic device. Further, the charging operationis interrupted.

If the received detection signal is discerned as data information on theunique ID of the non-contact power receiving apparatus 30 that can becharged without contacts, the received detection signal in response toload modulation is analyzed and discerned (unique ID discerning S02). Inthe standby mode S01, a search signal for the non-contact powerreceiving apparatus 30 is transmitted and a call signal requesting datainformation on the unique ID of the non-contact power receivingapparatus is also transmitted. Correspondingly, in the non-contact powerreceiving apparatus 30, induced current from the secondary charge core32 is rectified by the rectifier block 33 and is then filtered by thesmoothing filter block 34. During this procedure, the call signalrequesting the unique ID data information is transmitted to the devicecontroller 390 of the power receiver control unit, and correspondingly,unique ID data of the non-contact power receiving apparatus 30 stored inthe device memory 391 is transmitted to the non-contact powertransmission apparatus 10 through the signal processing block 392. Then,the main control unit 210 discerns whether or not the correspondingnon-contact power receiving apparatus is a normal apparatus that can becharged without contacts. That is, the main control unit 210 discernswhether or not the received data is a unique ID data type of a normalnon-contact power receiving apparatus, and then discerns whether or notthe received data is unique ID data transmitted from a normalnon-contact power receiving apparatus.

If the received data is discerned as unique ID data transmitted from anormal non-contact power receiving apparatus, the primary charge core 13is caused to generate a full power transmission signal through the gatedriver module 23 (full power transmission S03).

Describing the full power transmission S03 in the non-contact powertransmission apparatus 10, the main controller 210 of the centralcontrol unit 21 determines that a normal non-contact power receivingapparatus is placed on the charge plate (not shown), thereby generatinga control signal to transmit a power signal through the gate outputsignal processing block 213 and the gate signal lines 234.

The control signal generated as above is transmitted to the gate drivermodule 23 and is transmitted through the full bridge resonant converter22 to the primary charge core 13, which then generates an inducedmagnetic field, such that the power signal is transmitted to thenon-contact power receiving apparatus.

The gate signal lines 234 and the gate driver module 23, associated withthe above-described process, can have a construction as rendered in afollowing embodiment.

The control signal of the main controller 210 is transmitted through thegate signal lines 234 to the gate driver module 23. The gate drivermodule 23 can be constructed to include a gate signal converter 232performing gate signal processing on the control signal, an outputdriver 233 transmitting the processed signal to the full bridge resonantconverter 22, a gate controller 231 and so on.

The gate controller 231 can be constructed to control the signaltransmitting/receiving and processing operations in the gate drivermodule 23. Thereby, the control signal from the main controller 210 istransmitted to corresponding parts, and a resultant power signal istransmitted and an induced magnetic field is stably generated.

Next, in the charging operation, a signal requesting charge statueinformation is transmitted to the non-contact power receiving apparatus30, and the charge level of the non-contact power receiving apparatus 30is adjusted based on the charge status information (adjustment ofcharging S04).

Then, after the full power transmission S03, the non-contact powerreceiving apparatus 30 charges the power, supplied through the rectifierblock 33 and the smoothing filter block 34, in the battery cell 35through the charge IC block 36 and the PCM block 37 by the control ofthe device controller 390.

In response to this charging operation, the device controller 390 isinputted with information on the charge status through the charge ICblock 36 and the PCM block 37, and temporarily stores the charge statusinformation in the device memory 391. When the battery cell 35 is fullycharged, the device controller 390 controls the charge IC block 36 toterminate the charging operation and controls to generate fully-chargedstatus information from the secondary charge core 32 through the signalprocessing block 392. Further, if the voltage of the charged batterycell 35 is lower than a predetermined reference voltage, the chargingoperation can be resumed. If it is discerned fully-charged status, thecharging operation is terminated (No operation).

Accordingly, in the adjustment of charging S04, the main controller 210of the non-contact power transmission apparatus 10 requests statusinformation on stepwise charge level from the non-contact powerreceiving apparatus 30. As a response, the device controller 390 of thenon-contact power receiving apparatus 30 transmits the charged statusinformation to the non-contact power transmission apparatus 10 by loadmodulation.

The charged status information from the non-contact power receivingapparatus is transmitted through the received signal processing module24 to the main controller 210 connected to the received signalprocessing block 214. The signal processing module 24 includes areceived signal input 243 receiving a signal detected by loadmodulation, a received signal processor 242 converting the signaldetected by load modulation and a received signal controller 241controlling the operation of the received signal processing module 24.

According to this construction, the transmission information of thenon-contact power receiving apparatus 30 received through loadmodulation is signal-converted in the received signal processing module24 and is then transmitted to the main controller 210 through thereceived signal processing block 214. The received signal processingmodule 24 may generally include a plurality of amplifiers, a low passfilter (LPF), an OR circuit and so on.

When signals in response to load modulation are transmitted, a pluralityof the received signal processors 242, constructed in accordance with anembodiment, processes respective signals and transmits the processedsignals to the main controller 210 through received signal lines 244.

Accordingly, the non-contact power transmission apparatus 10 requeststhe data information on the charge level of the non-contact powerreceiving apparatus 30, particularly, via the gate driver module 23 andthe primary charge core 13. As a response, the non-contact powerreceiving apparatus 30 transmits the data information on the chargelevel of the battery cell 35, received via the charge IC block 36 andthe PCM block 37, to the non-contact power transmission apparatus 10.The data information is then transmitted to the main controller 210through the primary charge core 13 and the received signal processingmodule 24.

As an alternative construction, when the voltage of the power signalreceived from non-contact power receiving apparatus 30 is determined tobe lower or higher than a reference voltage, a corresponding signal canbe transmitted to the non-contact power receiving apparatus 10 so as toadjust the voltage of the power signal. For example, as shown in FIG.18, when the non-contact power receiving apparatus 30 moves to an outerarea while being properly charged in the central area of the chargeplate, the voltage of a received power signal is relatively lowered. Tocompensate for the lowered value, a voltage step-up request signal istransmitted to the non-contact power transmission apparatus 10.Conversely, as shown in FIG. 19, when the non-contact power receivingapparatus 30 moves to the central area from the outer area of the chargeplate, a relatively better power signal is received, in which thevoltage of the power signal is relatively raised. Then, a voltagestep-down request signal is transmitted to the non-contact powertransmission apparatus 10 in order to stably receive power.

Describing the adjustment of charging S04 during the charging operationin accordance with an embodiment of the present invention, thenon-contact power transmission apparatus 10 requests data on the chargedstatus information (charge capacity information) from the non-contactpower receiving apparatus 30. As a response, the non-contact powerreceiving apparatus 30 transmits a signal including charge informationdata, such as the charge capacity data and the charged statusinformation on the voltage of received power, and the non-contact powertransmission apparatus receives the signal including the chargeinformation data (step of receiving charge information data S042).

Data analysis and discerning is performed on the charged statusinformation of the power signal transmitted from the non-contact powerreceiving apparatus (step of discerning power data S043). A compensationfrequency with respect to the voltage data on the power signaltransmitted from the non-contact power receiving apparatus 30 iscalculated and a compensated power signal having the compensationfrequency is transmitted (step of transmitting compensated power signalS044).

In the above-mentioned example, the voltage of the received power signalacting as a reference in the non-contact power receiving apparatus 30was 5V. In this case, it is assumed that the voltage 5V be stablyreceived when the non-contact power receiving apparatus 30 does notmove. However, when the voltage of the received power signal drops orrises in response to the movement of the non-contact power receivingapparatus 30, the non-contact power transmission apparatus 10 modifiesthe frequency of the transmission power signal in order to compensatefor a variation in the voltage of the received power signal, such thatthe non-contact power receiving apparatus 30 can receive the powersignal at a stable voltage.

Accordingly, a compensation frequency variation Δf of the transmittingpower signal can be suitably determined based on the setting of thenon-contact charging system A, the non-contact power transmissionapparatus 10 and the non-contact power receiving apparatus 30. Forexample, the compensation frequency variation Δf can be variously setwith 10 Hz, 50 Hz, 100 Hz, 500 Hz, 1 KHz, 2 KHz, 5 KHz and so on.

Based on data indicating the charge level of the non-contact powerreceiving apparatus 30, the main controller 210 of the central controlunit 21 displays the charge level or the state information using lettersor a diagram on the LCD panel 153 through the signal output block 212and also controls the charge status indicator LED module 154 to indicatethe charging operation. Further, the charge status indicator LED module154 is lighted in various fashions to indicate different statuses. Forexample, the charge status indicator LED module 154 may be turned off toindicate the termination of the charging operation, or flicker toindicate the charging operation. In addition, a green lamp of the chargestatus indicator LED module 154 may be turned on to indicate thefully-charged status, and a red lamp of the charge status indicator LEDmodule 154 may be turned on to indicate an error caused by a foreignmaterial, a unique ID error, and etc.

When the non-contact power receiving apparatus 30 moves on or from thecharge plate during the charging operation, the power signal transmittedfrom the non-contact power transmission apparatus 10 can be varied so asto optimize the charging efficiency of the non-contact power receivingapparatus 30.

Then, information on the fully-charged status is received from thenon-contact power receiving apparatus 30, the fully-charged status isdisplayed using the LCD panel 153 or the charge status indicator LEDmodule 154, corresponding to a charging block 14, and the chargingoperation in the charging block 14 is terminated (fully-charged stageS06).

Preferably, the user can remove the fully-charged non-contact powerreceiving apparatus 30 from the stopped charging block 14, and leave thecharging block 14 in the standby mode until a starting signal isinputted.

In the case of foreign material error (a PMD error) or ID error status,an error status is displayed and the operation is interrupted in orderto ensure stability for the non-contact power transmission apparatus 10,the non-contact power receiving apparatus 30, a metallic object, oranother electronic device. Accordingly, when the operation isinterrupted due to an error, the process can preferably remain in thestandby mode until a restarting signal is inputted from the user.

Of course, in the case of the error status or the fully-charged status,a pulse signal can be periodically transmitted, the non-contact powerreceiving apparatus 30 can be detached or the foreign material can beremoved so as to remove the error based on a signal caused by resultantload modulation. Then, the process can be converted into a normalstandby mode.

Furthermore, when the power signal is received in response to therequest signal from the non-contact power transmission apparatus 10, thedevice controller 390 of the non-contact power receiving apparatus 30can control the data value of the voltage of the power signal to betransmitted to the non-contact power transmission apparatus 10.

A description will be given of charge-related procedures in thenon-contact power receiving apparatus 30. In the standby mode of thenon-contact power receiving apparatus 30 for receiving a power signal, acall signal, transmitted together with an object detection signal fromthe primary charge core 13 of the non-contact power transmissionapparatus 10, is detected. Here, the call signal calls the unique IDvalue of the non-contact power receiving apparatus 30. Then, a signal onthe unique ID value of the non-contact power receiving apparatus 30 istransmitted to the non-contact power transmission apparatus (unique IDvalue transmitting step S21).

After the unique ID value transmitting step S21, the process isconverted into a charge standby mode and a power signal received fromthe non-contact power transmission apparatus 10 is rectified and is thencharged in the battery cell 35 (charging step S22).

Accordingly, a monitor module can be constructed to monitor the voltageof a power signal received from the non-contact power transmissionapparatus 10 in response to a request or by the control of the devicecontroller 390. It is discerned whether or not the voltage of thereceived power signal is a reference voltage, if the voltage of thereceived power signal is below the reference voltage, a voltageadjustment signal is transmitted to request voltage step-up. Conversely,if the voltage of the received power signal is above the referencevoltage, the voltage adjustment signal requests voltage step-down(voltage adjustment requesting step S23).

When a voltage received after the voltage adjustment requesting step S23is a reference voltage, a signal indicative of normal reception istransmitted (normal voltage signal transmitting step S24). It isdiscerned whether or not the battery cell 35 is fully charged, and inthe case of the fully-charged status, the charging operation isterminated (charging operation terminating step S25).

In the voltage adjustment requesting step S23, the level of the voltageof the received power signal can be discerned, and the charge level ofthe battery cell 35 can also be discerned.

In the case of discerning the voltage of the received power signal, asshown in FIG. 18 where the non-contact power receiving apparatus 30 ismoved to the outer area from the central area of the non-contact powertransmission apparatus 10, received power is temporarily weakened sincethe non-contact power receiving apparatus 30 is located relatively in anouter position with respect to the primary charge core 13. When anormally-received voltage is 5V, the low voltage monitor module 311 ofthe received power monitor module 31 detects a voltage 4.5V indicativeof a voltage drop −0.5V. Accordingly, a signal requesting thestepping-up of transmission power (a power-up request signal) istransmitted to the non-contact power transmission apparatus 10.

Further, as shown in FIG. 19, the non-contact power receiving apparatus30 is moved to the central area from the outer area of the non-contactpower transmission apparatus 10, where a stable voltage of about 5V isreceived. Here, received power is temporarily intensified since thenon-contact power receiving apparatus 30 is located relatively in acentral position with respect to the primary charge core 13. Then, thelow voltage monitor module 311 of the received power monitor module 31detects a voltage 5.5V indicative of a voltage rise 0.5V. Accordingly, asignal requesting the stepping-down of transmission power (a power-downrequest signal) is transmitted to the non-contact power transmissionapparatus 10.

As a result, the non-contact power transmission apparatus 10 can modifythe frequency of the transmission power signal, such that the powersignal can be received and charged at a more stable voltage. The stablereception of the voltage can be observed from graphs of FIGS. 13 to 16.

Below, a detailed description will be given of the power control processin accordance with the adjusting of charging.

As shown in FIGS. 7 and 13 to 16, a power signal transmitted from theprimary charge core 13 of the non-contact power transmission apparatus10 is received through the secondary charge core 32 of the non-contactpower receiving apparatus 30. Here, information on the intensity of theinput voltage of the power signal is sent to the device controller 390.

If the voltage of the received power signal is detected as beingtransmitted at a stable voltage (e.g., 5V), the voltage can preferablybe maintained to be uniform. Conversely, if the voltage of the receivedpower signal is too low or high, information on voltage adjustment istransmitted by load modulation to the non-contact power transmissionapparatus 10, such that a uniform value of voltage can be received. Whenthe voltage is adjusted to be uniform, the operation of the charge IC ofthe charge IC block 36 of the non-contact power receiving apparatus 30is activated by the control of the device controller 390, such that thepower can be charged in the battery cell 35.

While the power transmitted from the non-contact power transmissionapparatus 10 is charged in the battery cell 35 of the non-contact powerreceiving apparatus 30, the PCM block 37 discerns whether or not thebattery cell 35 is stabilized in order to ensure a stable chargingoperation.

In the charging operation of the non-contact power charging system Aincluding the non-contact power transmission apparatus 10 and thenon-contact power receiving apparatus 30, as shown in FIGS. 18 and 19,when the non-contact power receiving apparatus 30 moves on the chargingplate of the non-contact power transmission apparatus 10, the primarycharge core 13 and the secondary charge core 32 are relocated, therebydropping the receptibility of the power signal in the non-contact powerreceiving apparatus 30. The location of the primary charge core 13 andthe secondary charge core 32 becomes less efficient with the distancebetween the centers of the cores, such that induced electromotive forceis rarely generated from the primary charge core 13 and the secondarycharge core 32.

Accordingly, in the non-contact power charging system A of the presentinvention, when the voltage of the power signal received in thenon-contact power receiving apparatus 30 placed on the charging blockdrops below or rises above the reference voltage, a compensation requestsignal is transmitted to the non-contact power transmission apparatus10, requesting the non-contact power transmission apparatus 10 totransmit a compensated power signal.

For example, it is assumed that the reference voltage of the receivedpower signal be 5V and a reference variation of the received voltage be+/−0.5V. As shown in FIG. 18, when the non-contact power receivingapparatus 30 is moved from the central portion to the outer portion, avoltage lower than 4.5V is received. Then, the control of the devicecontroller 390 of the non-contact power receiving apparatus control unit39 controls to transmit a voltage step-up request signal, such that thevoltage is stepped up about 0.5V. Here, the secondary charge core 32 iscontrolled through the signal processing block 392 to transmit thevoltage step-up request signal.

Further, as shown in FIG. 19, when the non-contact power receivingapparatus 30 is moved from the outer portion to the central portion, avoltage higher than 5.5V is received. Then, the control of the devicecontroller 390 of the non-contact power receiving apparatus control unit39 controls to transmit a voltage step-down request signal, such thatthe voltage is stepped down about 0.5V. Here, the secondary charge core32 is controlled through the signal processing block 392 to transmit thevoltage step-down request signal.

In response to the voltage step-up request signal or the voltagestep-down request signal, the non-contact power transmission apparatus10 transmits a compensated power signal, which is compensated for 0.5V.As an example of increasing the power signal transmitted from thenon-contact power transmission apparatus 10, it can be controlled tomodify the oscillation frequency.

As such, the power signal transmitted from the non-contact powertransmission apparatus 10 is adjusted according to the location of thenon-contact power receiving apparatus 30. The charging efficienciesaccording to the replacement are illustrated in the graphs of FIGS. 13to 16.

In the test reported in FIGS. 13 to 16, the reference power in thesecondary side of the non-contact power receiving apparatus 30 was onthe order of 2.5W. While the non-contact power receiving apparatus 30was being moved horizontally and vertically moved on the charging plateof the non-contact power transmission apparatus 10 to a distance rangingfrom −7 mm to 7 mm, primary side power W at the non-contact powertransmission apparatus 10, secondary side power W at the non-contactpower receiving apparatus 30 and the resultant efficiency (%) weremeasured and calculated. The efficiency (%) is produced by dividing theoutput power in the secondary side of the non-contact power receivingapparatus 30 with the input power in the primary side of the non-contactpower transmission apparatus 10 as expressed in the formula:

efficiency (%)=(secondary side power)/(primary side power)*100.

In the meantime, FIGS. 11 to 14 illustrate graphs related with powercompensation tests, in which transmission power compensation was 0.5W,and the secondary side power in the non-contact power receivingapparatus was in the range from 2 to 2.5W. Here, the charging efficiencyin the non-contact power transmission apparatus was obtained by changingthe horizontal and vertical distance between the non-contact powertransmission apparatus and the non-contact power receiving apparatus.Particularly, FIGS. 11 and 12 illustrate cases in which powercompensation according to frequency modification was not applied. Here,when the non-contact power receiving apparatus was moving horizontallyor vertically with respect to the non-contact power transmissionapparatus, the secondary side power of the non-contact power receivingapparatus decreased with the distance from the center, thereby loweringthe charging efficiency.

Comparatively, FIG. 13 shows a graph resulting from horizontal movementand FIG. 14 shows a graph resulting from vertical movement in thenon-contact charging system A of the present invention. Information onthe voltage variation of the received power in the non-contact powerreceiving apparatus was transmitted when the non-contact power receivingapparatus 30 was moving horizontally or vertically on the top surface ofthe charging block 14 of the non-contact battery pack as an example ofthe non-contact power transmission apparatus 10. In response to thisinformation, the non-contact power transmission apparatus 10 controlled(compensates for) power through frequency modification. Referring to theefficiencies in the graphs, power transmission was stable and thus powertransmission efficiency was also good.

FIG. 15 is an efficiency graph related with the horizontal movement, andFIG. 16 is an efficiency graph related with the vertical movement.Referring to FIGS. 15 and 16, the charging efficiencies of compensatedpower transmission according to frequency modification (square-dottedprofiles in the upper part, Power Control) were better than thosewithout compensated power transmission according to frequencymodification (circle-dotted profiles in the lower part, Fixed Power).

Accordingly, the non-contact power charging system A including thenon-contact power transmission apparatus 10 and the non-contact powerreceiving apparatus can stably transmit power without contacts. Thenon-contact power transmission apparatus 10 and the non-contact powerreceiving apparatus 30 of the non-contact power charging system A can beused as a stable system.

When the user touches the non-contact power receiving apparatus 30 orthe non-contact power transmission apparatus 10 shakes during thecharging operation, the relative location of the primary charge core ofthe non-contact power transmission apparatus 10 and the secondary chargecore of the non-contact power receiving apparatus 30 may be changed.However, the charging power compensation as described above makes itpossible to charge the non-contact power receiving apparatus 30 with astable voltage, such that the non-contact power receiving apparatus 30can be charged in succession before being fully charged.

As shown in FIGS. 9, 10 and 17, the non-contact power receivingapparatus 30 of the present invention also includes a shield member,which protects the non-contact power receiving apparatus 30 and thebattery cell 35 from a magnetic field generated by the primary chargecore 13 of the non-contact power transmission apparatus 10 and thesecondary charge core 32 of the non-contact power receiving apparatus30.

Firstly, FIG. 9 is an exploded perspective view illustrating theconstruction of the non-contact power receiving apparatus 30 having awireless power receiver module. The non-contact power receivingapparatus 30 is made of a coil, fine metal, a thin sheet of aluminum(e.g., an aluminum foil), and lithium ion or lithium polymer includesAluminum in order to shield a magnetic field 100%, so that the cell canbe free from the influence of the magnetic field. As a result, the cellcan be charged and discharged for a predetermined cycle of 500 times ormore. Here, the secondary charge core can have any core shapes. That is,the shape of the secondary charge core can include a quadrangle, acircle and an ellipse, and can be implemented as various types of coressuch as a wound core and a spiral core. Accordingly, the non-contactpower receiving apparatus 30 having a wireless power receiver moduleincludes a wireless power receiver circuit 40 on one lateral side of therechargeable battery cell 35 and a shied member 41 surrounding thewireless power receiver circuit 40. The wireless power receiver circuit40 is constructed including some parts of the non-contact powerreceiving apparatus 30, such as the power receiver control unit 39 andthe charge IC block 36.

Further, shielding plates 42, 43, 44, 45 and 46 are provided on thebottom and four side surfaces of the battery cell 35, respectively, toshield a magnetic field from the primary charge core and the secondarycharge core 32 so as to protect the battery cell 35 from the magneticfield.

A total of five (5) shielding plates 42 to 46 is provided in total fivedirections including the four lateral directions and the downwarddirection of the battery cell 35 to completely shield the magnetic fieldfrom the primary charge core and the secondary charge core 32 so as toprotect the battery cell 35 from being damaged by the magnetic field.Alternatively, a shielding plate can also be provided on the top surfaceof the rechargeable battery cell 35 if temperature rise due to thecompletely-enclosed structure of the battery cell 35 does not cause atrouble.

The shielding plates 42 to 46 and the shielding member 41 can be formedas a thin sheet of metal such as Al, Cu or Ni alloy.

Further, magnetic plates 48 are provided between the shielding plate 46,which is placed under the battery cell 35, and a charge receiver module321 having the secondary charge core 32. The magnetic plates 48 help themagnetic field be better induced to the secondary charge core 32. Themagnetic plates 48 may be constructed of amorphous ferrite, Mn—Zn (50parts by weight: 50 parts by weight), Ni—Fe (80 parts by weight: 20parts by weight), or fine metal (Fe—Si—Cu—Nb).

The magnetic plates 48 include an upper magnetic plate 481, placedbetween the shielding plate 46 and the charge receiver module 321, and alower magnetic plate, placed under the charge receiver module 321. Thelower magnetic plate 482 is formed with a lower plate through-hole 483,which extends vertically through the lower magnetic plate 482,particularly, the central portion of the lower magnetic plate 482. Theshape of the lower plate through-hole 483 may preferably conform to thatof the secondary charge core 32. Accordingly, FIG. 16 illustrates anexample in which the lower plate through-hole 483 of the lower magneticplate 482 was circular-shaped in order to conform to the circular shapeof the secondary charge core 32. Of course, when the core isquadrangular- or polygonal-shaped, the lower plate through-hole 483 maypreferably be shaped in the same shape. The lower plate through-hole 483configured as above helps induced electromotive force be better formedin the second charge core 32 in an induced magnetic field and signals bebetter transmitted.

An insulating plate 47 is further provided between the battery cell 35and the shielding plate 46 below the battery cell 35 to insulate thebattery cell 35. The insulating plate 47 is implemented with a meshmember or a thin film of Ni—Cu so as to prevent the heat of theshielding plate 46 from being conducted to the battery cell 35.

FIG. 10 shows another form of the magnetic field shielding member, whichincludes a battery cell case 35′ of aluminum encasing the battery cell35, a magnetic plate 48 of first Hanrim Postech electro-magnetic shield(HPES), which is placed between the battery cell case 35′ and thesecondary charge core 32, and a shielding mesh member 49 of second HPES,which is sandwiched between the magnetic plate 48 of first HPES and thebattery cell case 35′. The magnetic plate 48 of first HPES and theshielding mesh member 49 of second HPES can have a composition the sameas that of the above-described shielding member.

The magnetic plate 48 of first HPES shields a majority of magneticfield, such that magnetic lines of force are bent by the magnetic plate48 acting as a shielding plate, and thereby do not influence on thebattery cell (see FIG. 17). The magnetic lines of force generate heat inthe top portion, and the heat is dissipated to the outside by themagnetic plate 48 made of metal. Further, the shielding mesh member 49of second HPES is constructed with a mesh metal sheet coated with acoating agent composed of amorphous ferrite, Mn—Zn (50 parts by weight:50 parts by weight), Ni—Fe (80 parts by weight: 20 parts by weight), orfine metal (Fe—Si—Cu—Nb). As such, the shielding mesh member 49 ofsecond HPES serves to shield a remaining portion of the magnetic linesof force, which are not shielded by the magnetic plate 48 of first HPES.The mesh metal sheet of the shielding mesh member 49 of second HPESgenerate eddy current, which in turn protects the battery pack from themagnetic field generated by the primary charge core and the secondarycharge core. According to tests, the magnetic plate 48 of first HPESshields about 90% and the shielding mesh member 49 shields about 10% ofthe magnetic field.

500 times (500 cycles) of charging/discharging tests were performed onthe non-contact power receiving apparatus 30 to which the magnetic plate48 of first HPES and the shielding mesh member 49 of second HPES areapplied. In FIG. 17, the reference was that the battery and the chargingsystem were not charged and discharged without contacts but were chargedand discharged via wires. When 500 times of charging and dischargingwere stably repeated, an efficiency curve of about 80% was set asreference efficiency segment (D). In FIG. 17, the graph shows the testresults compared to the reference efficiency segment (D) of about 80%.Here, “N” indicates a resultant profile of a test using electricalcontacts connected by wires without exposure to a magnetic field. Theprofile “N” of this test is positioned above the reference efficiencysegment, thereby showing stable efficiency.

Comparably, in FIG. 17 indicates a profile of a test using thenon-contact power receiving apparatus 30 of the invention, to which themagnetic plate 48 of first HPES, the shielding mesh member 49 and thelike were applied. In this test profile, stable efficiency of 83.9% wasobserved at 500 times of charging and discharging.

However, when second HPES was not applied (i.e., in a profile indicatedwith “B” in FIG. 17), efficiency of 75.3% was observed at 460 times ofcharging and discharging. When neither first HPES nor second HPES wasapplied (i.e., in a profile indicated with “C” in FIG. 17), poorefficiency of 74.5% was observed at 340 times of charging anddischarging, which fall short of the reference 500 times. It can beunderstood that the test of the invention has much better efficiency.

While the present invention has been described with reference to theparticular illustrative embodiments and the accompanying drawings, it isnot to be limited thereto. Accordingly, the foregoing embodiments can besuitably modified and altered, and such applications fall within thescope and spirit of the present invention that shall be defined by theappended claims.

1-5. (canceled)
 6. A method of controlling a non-contact power chargingsystem, comprising: generating a power transmission signal in anon-contact power transmission apparatus and transmitting the powertransmission signal to a non-contact power receiving apparatus to chargethe receiving apparatus; receiving charging information from thereceiving apparatus; and adjusting a level of the power transmissionsignal transmitted to the receiving apparatus by adjusting a frequencyof the power transmission signal, based on the charging informationreceived from the receiving apparatus.
 7. The method of claim 6, whereinthe charging information comprises a request to lower a level of thepower transmission signal which is transmitted from the receivingapparatus if any one of voltage and current measured in the receivingapparatus is greater than an upper limit of a predetermined range, or arequest to raise a level of the power transmission signal which istransmitted from the receiving apparatus if any one of voltage andcurrent measured in the receiving apparatus is less than the lower limitof the predetermined range.
 8. The method of claim 6, further comprisingtransmitting an object detection signal from the transmission apparatusto the receiving apparatus, the objection detection signal comprising acall signal for requesting a unique identifier signal from the receivingapparatus, wherein generating and transmitting the power transmissionsignal occurs when the unique identifier is received from the receivingapparatus in response to the call signal.
 9. The method of claim 8,further comprising entering into a standby mode after transmitting theobject detection signal and prior to receiving the unique identifiersignal from the receiving apparatus.
 10. The method of claim 6, whereinthe charging information comprises charging status information and themethod further comprises terminating a charging operation if thecharging status information is indicative of a fully-charged state. 11.The method of claim 10, further comprising displaying the chargingstatus information.
 12. The method of claim 6, wherein the charginginformation is transmitted by load modulation.
 13. A non-contact powercharging system, comprising: a non-contact power transmission apparatuscomprising: a primary charge core for generating a power transmissionsignal and transmitting the power transmission signal to a non-contactpower receiving apparatus to charge the receiving apparatus; a receivedsignal processor configured to receive the charging information from thereceiving apparatus; and a central control unit configured to receivethe charging information processed in the received signal processor andadjust a frequency of the power transmission signal so as to adjust alevel of the power transmission signal transmitted to the receivingapparatus.
 14. The system of claim 13, wherein the charging informationcomprises a request to lower a level of the power transmission signalwhich is transmitted from the receiving apparatus if any one of voltageand current measured in the receiving apparatus is greater than an upperlimit of a predetermined range, or a request to raise a level of thepower transmission signal which is transmitted from the receivingapparatus if any one of voltage and current measured in the receivingapparatus is less than a lower limit of the predetermined range.
 15. Thesystem of claim 14, wherein the non-contact power receiving apparatus isconfigured to measure the any one of voltage and current supplied to thereceiving apparatus, compare the measured any one of voltage and currentwith the upper limit and the lower limit of the predetermined range, andtransmit to the transmission apparatus, the request to lower the levelof the power transmission signal if the measured value is greater thanthe upper limit, or the request to raise the level of the powertransmission signal if the measured value is less than the lower limit.16. The system of claim 13, wherein the central control unit isconfigured to transmit an object detection signal from the transmissionapparatus to the receiving apparatus, the objection detection signalcomprising a call signal for requesting a unique identifier signal fromthe receiving apparatus, wherein the central control unit is configuredto generate and transmit the power transmission signal when the uniqueidentifier is received from the receiving apparatus in response to thecall signal.
 17. The system of claim 16, wherein the central controlunit is configured to enter into a standby mode after transmitting theobject detection signal and prior to receiving the unique identifiersignal from the receiving apparatus.
 18. The system of claim 13, whereinthe charging information comprises charging status information and themethod further comprises terminating a charging operation if thecharging status information is indicative of a fully charged state. 19.The system of claim 18, further comprising displaying the chargingstatus information.
 20. The system of claim 13, wherein the charginginformation is transmitted by load modulation.